The usage of mobile communications systems utilizing mobile devices has become widespread. Retail stores and warehouses, for example, use such systems to track inventory and replenish stock. This information is entered by employees using a hand held or portable communication unit which can be carried through the store or warehouse. In a medical environment, these systems can reduce the time needed to fill out forms and eliminate inaccuracies by allowing medical personnel to transmit data directly from a mobile communication unit carried by the medical personnel.
Conventional systems allow users to access fixed base stations (e.g. access points) interconnected by a cable medium to form a hardwired network backbone. Each base station has a service area or cell surrounding the base station within which it is able to transmit and to receive data from other mobile communication units within the area. Also included in many systems are intermediate access points which are not connected to the network backbone but otherwise perform many of the same functions as the fixed access points. Intermediate access points, often referred to as wireless access points or base stations, increase the area within which access points connected to the system backbone can communicate with mobile devices. Unless otherwise indicated, the term “access point” will hereinafter refer to both access points hardwired to the system backbone and wireless access points.
Associated with each access point is a geographic cell. Such cell is a geographic area in which an access point has sufficient signal strength to transmit data to and receive data from a mobile device, such as a terminal or telephone with an acceptable error rate. Typically, access points will be positioned along the backbone such that the combined cell area coverage from each access point provides full coverage of a building or site.
Mobile devices such as telephones, pagers, personal digital assistants (PDAs), data terminals, etc. are designed to be carried through the system from cell to cell. Each mobile device is capable of communicating with the system backbone via wireless communications between the mobile device and an access point to which the mobile device is registered. As the mobile device roams from one cell to another, the mobile device will typically deregister with the access point of the previous cell and register with the access point associated with the new cell.
These systems provide acceptable coverage areas but do not provide information about the various external devices within the cell which a user can automatically locate and connect to or access to perform desired functions. Users need this type of capability to locate specific external devices, such as charging devices, synchronization devices, or other peripherals required for the work process and need to do this without having to spend time manually searching for devices.